1. Field of the Invention
The present disclosure relates to a solenoid of an electromagnetic valve.
2. Description of the Related Art
An electromagnetic valve is used for hydraulic control of an automatic transmission of a vehicle. This electromagnetic valve opens and closes a valve main body connected to a plunger in a hydraulic circuit by driving the plunger made of a piece of iron by the electromagnetic force generated from a solenoid. The solenoid of this electromagnetic valve includes a cylindrical bobbin and an enameled wire wound around the bobbin to form a coil.
Both end portions of the enameled wire wound around the bobbin extend to terminals for connecting with the outside, which are disposed on an outer side of one end of the bobbin, and are connected and fixed to the terminals. At this time, considering the workability when winding the enameled wire around the bobbin, both of the end portions of the enameled wire were formed to have a cross shape with a minute clearance, and respectively connected to the terminals. Further, in order to prevent a short circuit, some methods were adopted in which the cross portion is fixed by resin-molding or fixed with an adhesive. In the following description, the wiring with both of the end portions of the enameled wire formed in the cross shape is referred to as a cross wiring.
However, when the cross portion is resin-molded, the cross portion may be too narrow to function as a flow path for the resin mold, and the enameled wire of the cross portion may be pulled. When temperature change is repeated in this state, the enameled wire may break and become disconnected.
In order to prevent this disconnection, the cross portion may be protected with a UV-curable adhesive or a silicon rubber layer, which makes, however, the processes become complicated.
Alternatively, it may also be considered not to use the cross wiring. In this case, however, the enameled wire may become wider between a winding start portion and a winding end portion of the enameled wire, thereby causing breaking of the wire.